Recently, a statistic has been making the rounds on blogs, social media, and in the mainstream news: 74 school shootings have occurred since the shootings at Sandy Hook in late 2012. The statistic comes from a group that has a rather explicit agenda: Everytown for Gun Safety. While it does give us some information about an important social phenomenon, my initial feeling about this statistic is that when taken out of context (and it is almost always shown without any context), it is apt to mislead.
First, there's the question of how we define "similar events". Do we count incidents in which guns were discharged but didn't kill anyone, or injure anyone? Do we count homicides related to drug deals? Do we count suicides? Do we count accidental gun discharges? Do we count colleges as well as elementary and secondary schools? In the case of the above statistic, Everytown for Gun Safety has counted all of these as "school shootings".
Why does it matter how inclusive our definition of "school shootings" is? Aren't all of these shootings horrible events that we should seek to avoid? In my opinion, yes, absolutely. However, if we're trying to understand a certain social phenomenon and whether a string of recent events are part of a trend, broad definitions only muddy the water. The social and psychological processes involved in suicide-by-gun at or near schools is likely to be different in important ways than those processes as they are applied to individuals like Adam Lanza and Elliot Rodger. Obviously the common denominators are "school" and "gun", and if you're of the mind that gun control is the ONLY solution to the problem of any kind of school shooting, then you may not care about the differences. But you should. Even if you're in favor of gun control and you think it will cut down on the number of people who die each year in school shootings, it won't help to ignore other factors, and I think overly-broad definitions of "school shootings" encourage this kind of ignorance. Is the increase in school shootings due to an increase in angry-young-males lashing out at the world, an increase in drug/gang-related shootings, or both? In order to address the issue, it's important to know.
Is it really a trend? If you just tell someone how many incidents occurred in one year, that doesn't really give them a good idea of whether or not it is part of a potentially alarming trend. This is the real reason I'm writing about this. I was genuinely curious. I wanted to know if the headlines were part of a familiar kind of hysteria about a random rash of low-probability/high-consequence events or if they're on to something. It wasn't easy to tell just by reading the news or the blogs. But there IS data on this. It ain't perfect data, but I think it may help me get an answer, this is one of the things I absolutely love about today's Internet - you have access to data and can see for yourself whether there is evidence to support a conclusion.
I used this list from Wikipedia of school shootings in the U.S., defined as "incidents in which a firearm was discharged at a school infrastructure, including incidents of shootings on a school bus." It included K-12 schools as well as colleges and universities, so the definition is pretty similar to that used by Everytown for Gun Safety. The list draws from newspaper archives. By virtue of their newsworthiness, school shootings seem unlikely to have ever gone unreported, so I think we can safely assume that this list is a fairly accurate record of school shootings and doesn't contain much in the way of systematic measurement error.
Before I show you what I found, take a moment to guess: how many school shootings do you think there were in 1880? How about 1904? 1970?
(scroll down for the answers!)
Here's what I found:
So yeah, it does seem like there's something crazy going on in the last 18 months if you define school shooting this way. Why do I designate the last 18 months as the time period to pay attention to? It's about the time that the Adam Lanza killings occurred, and it's also near the beginning of the year, but these aren't good reasons to use this date as a cut-off. But if you look at the number of shootings per month, they really seem to go up in January of 2013.
There is plenty of seemingly random year-to-year variation across the whole 164 year period, but the number of incidents tend to fluctuate between 0 and 5 per year. It's worth noting that the last year there were no school shootings was 1981, so you could use that as a the beginning of the trend if you really wanted to.
It was weird for me to read about children shooting themselves in the early 1900's at school. It doesn't fit with my conception of the culture at the time. So school shootings aren't unprecedented, but after looking at this data, it seems hard to deny that the problem has gotten much worse in the past few years (or possibly since 1995 or 2005). If there were, say, 10 school shootings in 2013, I think you could possibly say that it was due to random variation. But there have been 31 in the first half of 2014!
What if we dig a bit deeper and look at the circumstances around each shooting. Do we see differences between the shootings from, say, the early 1900's and the shootings of today? In my search through the shootings since the 1850's in schools, I tried to isolate ones that I thought were similar to Sandy Hook: not suicide; not accidental; and not directed at one particular individual for reasons of, say, revenge or a rejection; not gang-related. I call this kind of shooting "mass school shootings". I include cases in which an individual clearly attempted a mass school shooting but was thwarted (though there are only a few of these, so they don't make much of a difference). Again, I must emphasize: I'm not saying that those other kinds of shootings aren't problems that need to be solved, but only that I want to isolate Sandy-Hook-ish shootings to see if there is indeed a trend. Here's what I found:
Note that the Y axis is different than the Y axis in the first graph. If I had used the same Y axis in both graphs (or included both lines in the same graph), it would've been hard to see the mass shootings line, so this is why I used two different y axes.
If you look at most of the school shootings pre-1966, they're directed at a particular individual and the motives are typically revenge (for a bad grade or being rebuffed by a would-be lover). Again, it was weird to read about mass school shootings similar to Sandy Hook that took place in the 1800's (though there were just two, so it really was anomalous).
As you can see, there's a similar pattern to the pattern in the overall school shootings: not much happens until recently. But what do we mean by "recently"? You could easily put the starting point of the trend at 1985, the first year there were more than two separate incidents of mass school shootings. What about since Sandy Hook? Let's take a closer look at the data, starting at 1985:
So, 1985 was a bad year, and so were 1988, 1998 (the 90's in general were pretty bad for this type of thing) and 2006. 2013 (the only post-Sandy-Hook year in our data set) is bad, but not much worse than these other years. In the first half of 2014, there have been three mass school shootings, but it would be dangerous to extrapolate from that and estimate that there will be six for the year. Extrapolation with such small sample sizes rarely maps on to reality.
In the end, here's what I get from this little exercise. The truth, such as I can determine it from available evidence, is that school shootings in general have become a lot more common in the last 18 months, but it seems unwarranted to say that Sandy-Hook-style mass school shootings have become a lot more common in that same time period. If you wanted to identify a starting point for the cultural phenomenon of mass school shootings, you'd be better off going back to 1985. If I'm looking for a culprit or cause of this phenomenon, I wouldn't look at things that are going on right now in our culture and in our laws. I would look at things that have been around and haven't changed much since 1985.
As would be the case with any phenomenon, my attitude would change if new evidence warranted such a change. If there were no more school shootings this year, I'd stick to my interpretation: nothing new in the world of mass school shootings since '85. BUT if there were 3 or more, then I'd reconsider my outlook.
From looking at this data, I also get the impression that there is an urgent problem with shootings at schools, but that this problem isn't akin to the problem of Sandy Hook or Columbine. Like any compassionate person, I'm appalled at that rapid increase in school shootings you see in the first graph, and I want to know more about why it's occurring and what we can do to stop it. A lot of these school shootings are committed by sane people who have a deep disagreement with another person and (importantly) access to guns. If anything, I think this analysis makes the case of those who choose to pin the problem of school shootings on a lack of proper mental health care and not on gun availability (I'm looking at you, Wayne LaPierre!) a lot weaker. School shootings are skyrocketing, according to the evidence, and most incidents don't involve mental health issues as such. So, maybe addressing the issues of gun availability, conflict resolution, and, perhaps, a cultural component may be an effective way to lessen the number of overall school shootings.
This analysis does NOT make for an easily conveyed, pithy soundbite. Because they need something pithy, the news and bloggers and others have latched on to a pithy-put-misleading alternative - the "74 since Sandy Hook" stat. On the one hand, this stat may grab more people's attention, gets them to click and gets them to post. On the other hand, based on all the evidence I can see, it IS misleading. It's use opens up those trying to convince others of the severity of the issue to attacks based on their use of misleading statistics.
This is, I would say, a familiar story in the use of statistics related to emotionally-loaded, low-probability/high-consequence events. It's a story that's worth returning to when discussing media literacy.
One final note: in my search for information about this topic, I found this article on CNN that actually DID dig a little deeper and found results similar to my own. They found a few more "Sandy-Hook-like" shootings because their definition differed slightly from mine, and (importantly) they had no historical comparison so they can't really talk about trends, but still, it gave me hope for more context when reporting stats in news. Big ups to CNN (though you really need to stop with the auto-playing videos).
Data source: http://en.wikipedia.org/wiki/List_of_school_shootings_in_the_United_States#cite_ref-47
1 comment:
interesting
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